Compare / head-to-head

Claude Opus 5.5vsKimi K2.5

Claude Opus 5.5 leads 5 of 6 shared benchmarks. Claude Opus 5.5 has the larger context window (1M tokens).

Benchmarks from cited public sources; pricing from official pages; status from official provider feeds.

Shared benchmarks
5 – 1
Claude Opus 5.5 leads
Cheaper per token
—
list price, input + output
Larger context
Claude Opus 5.5
1M tokens
Providers
2 providers
Anthropic · Moonshot AI
Claude Opus 5.5
Anthropic · released 2026-09-22
textvision
Context
1M
Max out
128K
Input /1M
$4 ↗
Output /1M
$20 ↗
Cached /1M
$0.2
Scores
34 · 9 core
Kimi K2.5
Moonshot AI · released 2026-01-27
textvisionvideo
Context
256K
Max out
—
Input /1M
—
Output /1M
—
Cached /1M
—
Scores
26 · 14 core
Quality

Benchmark matrix

BenchmarkClaude Opus 5.5Kimi K2.5ΔEdge
Reported by both · 6
LMArena Elo1503.7 ↗1450.1 ↗+53.6Claude Opus 5.5
LMArena WebDev (LMArena)1815.4 ↗1435.8 ↗+379.6Claude Opus 5.5
SAGE (Vals AI)45.8% ↗49.9% ↗-4.1 ptKimi K2.5
SimpleBench (SimpleBench)88.4% ↗46.8% ↗+41.6 ptClaude Opus 5.5
SimpleQA Verified72.2% ↗epoch run34.3% ↗epoch run+37.9 ptClaude Opus 5.5
Vending-Bench 2 (Andon Labs)9235.25 ↗1198.46 ↗+8036.8Claude Opus 5.5
Only Claude Opus 5.5 reports · 28
GPQA Diamond90.6% ↗epoch runnot reported——
APEX-Agents (Mercor)73.5% ↗not reported——
AutomationBench 1.0.640% ↗not reported——
Chartography (with tools)89% ↗not reported——
CursorBench 4.057.8% ↗not reported——
EBR-bench (Epoch AI run)71.4% ↗epoch runnot reported——
FrontierCode v1.1 (Main)54.4% ↗not reported——
FrontierMath Tier 4 v2 (Epoch AI run)95% ↗epoch runnot reported——
FrontierMath Tiers 1-3 v2 (Epoch AI run)91.2% ↗epoch runnot reported——
FrontierSWE V2 (Proximal Labs)62.3% ↗not reported——
Furniture Assembly (Epoch AI run)83.3% ↗epoch runnot reported——
GDPval-AA v2.11846 ↗not reported——
Humanity's Last Exam (with tools)67.7% ↗not reported——
LiveBench Agentic Coding (LiveBench)71.7% ↗not reported——
LiveBench Coding (LiveBench)89.3% ↗not reported——
LiveBench Data Analysis (LiveBench)80.3% ↗not reported——
LiveBench Instruction Following (LiveBench)67% ↗not reported——
LiveBench Language (LiveBench)86.3% ↗not reported——
LiveBench Mathematics (LiveBench)97.1% ↗not reported——
LiveBench Reasoning (LiveBench)92.2% ↗not reported——
LMArena Agent (LMArena)0.1382 ↗not reported——
MirrorCode (Epoch AI run)77.4% ↗epoch runnot reported——
Mystery Game Puzzles (Epoch AI run)71% ↗epoch runnot reported——
OSWorld 2.0 (partial)81.8% ↗not reported——
OTIS Mock AIME 2024-2025 (Epoch AI run)100% ↗epoch runnot reported——
Terminal-Bench 4.066.4% ↗not reported——
Terminal-Bench 4.0 (Vals AI)65.2% ↗not reported——
Terminal-Bench Science 0.158.7% ↗not reported——
Only Kimi K2.5 reports · 20
SWE-bench Verifiednot reported76.8% ↗——
MMLU-Pronot reported87.1% ↗——
AIME 2025not reported96.1% ↗——
BrowseCompnot reported60.6% ↗——
GPQA-Diamondnot reported87.6% ↗——
HLE-Fullnot reported30.1% ↗——
HLE-Full (w/ tools)not reported50.2% ↗——
HMMT 2025 (Feb)not reported95.4% ↗——
IMO-AnswerBenchnot reported81.8% ↗——
LiveCodeBench (v6)not reported85% ↗——
LMArena Vision (LMArena)not reported1252.2 ↗——
MMMU-Pronot reported78.5% ↗——
OSWorld-Verified (XLANG)not reported63.3% ↗——
SWE-Bench Multilingualnot reported73% ↗——
SWE-Bench Pronot reported50.7% ↗——
SWE-bench Verified (Epoch AI run)not reported73.8% ↗epoch run——
Terminal Bench 2.0not reported50.8% ↗——
Toolathlon-Verified (HKUST)not reported33% ↗——
VideoMMMUnot reported86.6% ↗——
WeirdML (Håvard Tveit Ihle)not reported45.6% ↗——
Scores tagged "epoch" or "matharena" are independent runs, used only where the lab has not published its own; ⚠ marks rows MathArena flags as released after the competition. Higher is better on every row. Δ is Claude Opus 5.5 minus Kimi K2.5 in the benchmark's own unit. "Not reported" means the lab has not published that figure; it is not a zero. ↗ opens the source.
Specs & pricing

Side by side

SpecClaude Opus 5.5Kimi K2.5Edge
Context window1M tokens256K tokensClaude Opus 5.5
Max output128K tokens——
Input price / 1M$4 ↗——
Output price / 1M$20 ↗——
Cached input / 1M$0.2 ↗——
Input + output / 1M
Lower is cheaper. List prices; batch, tool and regional fees excluded.
$24——
Modalitiestext · visiontext · vision · videoKimi K2.5
Released2026-09-222026-01-27—
Cited benchmark scores3426—
Reliability

Provider status

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